This invention relates to a method of conversion of a single hull vessel to a double hull vessel.
Owing to international concern over oil spillage from tankers, the International Maritime Organization is putting in place regulations which mandate double hull tankers. Existing single hull tankers will need to be converted to double hulls within a specified period. (See Marpol Regulations effective from Jul. 6, 1995 for crude oil tankers over 20,000 tons DWT and product tankers over 30,000 tons DWT). In addition, the U.S. Oil Pollution Act of 1990 requires all existing tankers to have double bottoms by 1997.
It is therefore recognized that a method of converting vessels from a single hull to a double hull is required. Existing methods of conversion require the vessel to be docked in a dry dock, during which time the ship owners lose business. Known conversion techniques are carried out inside the vessel by adding a second hull within the existing hull. This has the disadvantage of reducing the available storage capability of the vessel.